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General Information - Add to lead The optic tectum projects through the reticular formation and interacts with motor neurons in the brain stem. These connections are important for the recognition and reaction to various sized objects, which is facilitated by excitatory optic nerve transmitters like L-glutamate. Recent lesion studies however have suggested that the tectum has no influence over higher-order motion responses like OMR or OKR, but may be more integral to lower-order cues in motion perception like in the identification of small objects.

- Zaidel Sanchez (11/30/18) Cited sources

Zebrafish Function

Disrupting visual experience early on in animal development results in a change in tectal activity. Changes in tectal activity resulted in an inability to successfully hunt and capture prey. Tectal development was demonstrated to be affected by intrinsic factors and visual cues. . Hypothalamus inhibitory signaling to the deep tectal neuropil is important in tectal processing in zebrafish larvae Heap LA, Vanwalleghem GC, Thompson AW, Favre-Bulle I, Rubinsztein-Dunlop H, Scott EK. Hypothalamic Projections to the Optic Tectum in Larval Zebrafish. Tectum structures within Zebrafish form early on in development. Within the first three days upon fertilization, Retinal ganglion cell begin appearing and the laminae of the tectal forms along with the periventricular layer. . The tectal neuropil contains structures including periventricular neurons axons and dendrites. The neuropil also contains GABAergic superficial inhibitory neurons located in stratum opticum. Instead, they have a much larger tectum that is hypothesized to carry out some of the visual processing that the cortex performs in mammals.

Development and structure

The optic tectum is the visual center in the non mammalian brain which develops from the alar plate of the mesencephalon. It has laminar or layered structure which allows for different cell types to be present on corresponding layers. One example of the layer specificity is the deep laminae which send output signals away from the tectum toward the motor neurons, specifically the pontine nucleus. The pontine nucleus is located in the basal pons and is responsible for sharing information between the cerebrum and cerebellum (Pontine nucleus). Another example is the superficial laminae which receive input from retinal ganglion cells.

- A review article about the development of the tectum specifically looking at the function of Engrailed (En) in tectum development.

https://www.sciencedirect.com/science/article/pii/S0960982215011665

- The classification of object size relies on the optic tectum. Glutaminergic tectal interneurons are required for small object approach. Behavioral responses to different size stimuli shift if the interneurons are removed as seen in zebrafish

http://eds.b.ebscohost.com/ehost/pdfviewer/pdfviewer?vid=1&sid=ae166edd-44bc-40ee-899b-42d9ee553f1e%40pdc-v-sessmgr06


 * Developing from the alar plate of the mesencephalon, the optic tectum is the visual center in the non-mammalian brain
 * The optic tectum has laminar structures
 * One example is the deep laminae which send output signals away from the tectum toward the motor neurons, specifically the pontine nucleus. The pontine nucleus is located in the basal pons and is responsible for sharing information between the cerebrum and cerebellum ( https://medical-dictionary.thefreedictionary.com/pontine+nucleus ).
 * Another example is the superficial laminae which receive input from retinal ganglion cells